Reducing Damage From Vehicle-Bollard Impacts

Foundation mounted bollards are typically installed in one of two ways. The first, least expensive way, is with a plate mounted bollard. These bollards are steel pipes welded to a flat steel plate that can be anchored to a hard surface using concrete anchors. This method of installation is quick and inexpensive, requiring the installer to drill four to eight holes in the concrete and bolt down the bollard with expansion or screw anchors.

The downside to this installation method, when used with a rigid bollard, is that the anchors are generally not strong enough to withstand anything more than a minor collision. The plate anchors often are pulled up and possibly the plate bends, leaving a post which leans and is no longer able to properly serve its purpose. Plate mounted bollards often require constant maintenance and replacement. removable bollards for driveways

The second method for installing bollards involves using a longer steel pipe and burying a portion of it deep in the ground. This method gives the bollard far more strength than surface mounted, however it can be very expensive to install if the surface is concrete and already poured. Installation in this case requires coring a hole in the surface using an expensive diamond bladed coring saw. These machines and their blades are expensive and require water cooling, creating a mess during installation. Once the concrete is cored and the bollard is in place, the hole must be backfilled with concrete to secure the bollard. For added strength, these bollards are often filled with concrete, as well. Though the bollard pipe itself is relatively inexpensive, this installation method is costly and time consuming.

Although very strong, there are significant disadvantages to core installations. Most importantly, there is no give to this system upon impact. Though desired in high security applications, any vehicle impacting such a bollard will be significantly damaged and its passengers at risk of injury. Loads carried by fork trucks can also be thrown given the jarring impact likely to occur. Further, the bollard or its foundation can be damaged by such an impact, again leaving a tilted and less effective barrier requiring costly maintenance to correct. Often the steel bollard itself is beyond repair and must be replaced with an entirely new bollard.

Another disadvantage of this type of installation is that it is a permanent installation with little flexibility for movement. In factory applications, equipment is often moved and rearranged. Bollards used to protect equipment or storage racks which are core-installed are not easily moved. The concrete surrounding the bollard must be broken out and the large remaining hole filled, leaving a factory floor full of unsightly patches. If the bollard itself is reusable after removal, the entire expensive installation process is started over at the new location.

Some designs have been created to attempt to solve these problems through the use of plastic or spring loaded bollards, however these designs suffer from a lack of strength. If the plastic is of insufficient stiffness, the entire function of access denial is lost. On the other hand, very stiff plastic designs have had difficulty with long term durability. Minor collisions tend to wear away at such devices, and in outdoor applications UV degradation becomes a concern.

Leave a Reply

Your email address will not be published. Required fields are marked *